Field of the Invention
The present invention relates to optical systems and image pickup apparatuses. The present invention more particularly relates to an optical system suitable for an image pickup apparatus with use of a solid-state image sensor, such as digital still cameras and digital video cameras, and to an image pickup apparatus including the optical system.
Description of the Related Art
Image pickup apparatuses with use of a solid-state image sensor, such as digital still cameras and digital video cameras, have spread. With recent development of higher-performance, smaller-size, and the like of imaging optical systems, small imaging systems are rapidly spreading in particular.
Such small imaging systems are demanded to have further higher performance and smaller size. In the case of single-focus optical systems in particular, larger-aperture systems are highly demanded. For example, Japanese Patent Application Laid-Open No. 7-199066 discloses a small single-focus optical system with a large-aperture, the system having sufficient close-distance performance and having an F-number smaller than 2.8.
However, in the optical system described in Japanese Patent Application Laid-Open No. 7-199066, chromatic aberration correction is insufficient, and so the performance of the optical system is not high enough.
Accordingly, an object of the present invention is to provide small, high-performance, and large-aperture optical system and image pickup apparatus which are suitable for a small imaging system.